AM/FM, CB ANTENNA SPLITTERS
(USA & Canada, only)
(for use only with a factory Mazda Miata antenna)
by Jeff Anderson Destin, FL 32501
One of the best accessories for your car is one of Jeff's Anderson's antenna splitter systems for Miata's. Made just for the year and model of your car. Easy "plug in system" to install. Make sure that you let them know that you belong to the Miata club. And of course mention that you heard of it here at Miatafun. We have installed them in all three of our Miata's. (Pictures of our installation!)
(Last updated 6/10)
o Allows the Miata's AM/FM antenna to also be used for CB
o Eliminates scratches from a magnetically mounted CB antenna
o Easy in-trunk installation that can be left in place
o Special made for high performance with each type Miata antenna
o Great for club drives and caravans to Miata events
FIXED ANTENNA MODELS
FA90-1 (1990 and 1991)....................... $93.30
FA92-7 (1992 thru 1997)....................... $93.30
FA99 (1999)........................................ $93.30
FA06-0*(2006 thru ----)........................ $93.30
*Requires replacement screw-on antenna mast (not provided) see below.
POWER ANTENNA MODELS
PA92-5 (1992 thru 1995)....................... $93.30
PA96 (1996)........................................ $93.30
PA97 (1997)........................................ $93.30
PA99-05(1999 thru 2005)...................... $93.30
(prices are subject to change)
Plus shipping and insurance, and payment method, in US funds:
USA -- Payment: USA Check, USA Postal or Bank Money Order
Canada -- Payment: Postal Money Order in USD
Payment (in USD) may alternately be by PayPal (non-credit card funded).
Your PayPal payment transaction must be funded with funds in your PayPal account, or bank account, not by a credit nor debit card. Your payment by PayPal must also include PayPal's payment fees (new, June, 2009).
PayPal's fees are:
Payment is not accepted in advance of availability.
Email your request and I'll get back to you with notification to send payment. Do not send payment until you've received specific notification.
Once payment is received antenna splitters are customarily mailed from the local post office twice or more per week.
I've been making Miata special antenna splitters for those on the Miata.net for more than ten years. I personally make them using more than 40 years of professional electronics engineering experience in radio communications and antenna designs. I can only make them as I can find time. When I don't have immediate availability I keep a waiting list to notify you when I have one available for your Miata. I attempt to maintain immediate availability, or if not, I can usually get one built for you within 30 days of your confirmed request.
All models are supplied with detailed instructions with drawings. The cable to the CB is approximately 10 feet long with a standard CB screw-in coaxial connector (PL-259). A BNC connector (type used with some CB walkie-talkies) is sometimes available by request, or an adapter can be used, Radio Shack, #278-120.
These Miata antenna splitters are special made and performance optimized for easy plug-in installation in the Miatas trunk. They can be left installed in the car with no noticeable effect on AM/FM radio reception.
They are not suitable for use with another type antenna -- THEY ARE ONLY FOR THE MIATA'S FACTORY ANTENNAS (except for the designated antenna mast replacement for 2006 and newer Miata's). Because of this they provide high-performance equal to or better than many commonly used types of magnetically mounted CB antennas, and do not noticeably degrade reception of AM or FM. For 2006 and later the Miata's antenna mount must be used with a screw-on replacement antenna mast.
Miata antenna splitters are built for the CB radio's 4-watt legal power limit to provide long life and very dependable operation in one of two nicely constructed boxes. The recently redesigned one is approximately 2 3/8 X 1 3/4 X 1 1/4 inches, and the previous one sometimes still available, is approximately 2 7/8 X 1 11/16 X 13/16 inches. Installation instructions continue to show drawings for the previous antenna splitter. Installation of the new version is the same.
They are made and preset for each specific Miata antenna type (or for 2006 and later, for the Miata's antenna mount with specified replacement antenna mast); however, due to variances in the Miata antenna and antenna mount from one sample to another, they may require resetting to precisely best match the antenna on your specific Miata. Without resetting, the preset user adjustment provides quite effective performance. They can best be set with a SWR meter. Instructions are provided to enable setting the splitter without using a SWR meter by just listening for maximum CB reception. SWR at band edges is less than 3:1 and typically around 1.1:1 at best-set center band CB channel.
For pre-2006's the antenna splitter's cable to the CB radio can be run directly into the car by simply folding the vertical carpet down behind a seat (for 1999 - 2005's temporarily unfastening some of the trunk's interior trim may make running the cable easier). The upper outside corner of the carpet is held in place by Velcro. Once the carpet is pulled down a hole into the trunk is exposed. The area behind the Velcro-held carpet makes a nice pocket for storing the CB cable when it's not being used. For 2006's and later, interior panels must be temporarily removed.
2006 AND LATER, ANTENNA MAST SWAP and TRIM PANELS
The short antenna on 2006 and later Miatas is too short for capturing enough CB radio wavelength for effective CB communications range. So, for Miata antenna splitter use you'll need to replace your Miata's short screw-on antenna mast with an aftermarket mast, e.g. Metra AW-RM22 (AW-RM22B for black) 30 11/16" tall. In early 2007 they were found available for $3.99, or $4.99 in black, from O'Reilly Auto Parts. An OEM antenna mast for any 1990-99 Miata, 31 1/2" tall, can be used adequately with the antenna splitter's preset setting, or with the user setting slightly reset to best optimize. Simply rotate the Miata's short antenna mast to unscrew, and then screw on the longer fixed antenna mast. It can be left in place, or the Miata's short antenna mast can be reinstalled when not using CB radio. Running the coaxial cable antenna line from the antenna splitter in the trunk to your CB radio in the car requires temporarily removing and unfastening some trim panels in the trunk and in the car.
POWER ANTENNA STAY-UP METHODS
To maintain the Miata's power antenna extended for CB radio use while the Miata's radio is turned "off" or while its tape or CD is played:
The power antenna splitter models for pre-97 Miatas include diode-connected clamp-type wire taps that install at the antenna's plug. The antenna extends when the car's key-switch is in its "on" and accessory positions and retracts when not.
The power antenna splitter model for 97 Miatas includes a jumper wire and wire taps that connects a wire at the antenna's plug to one that's behind the trunk's rear trim panel. The antenna extends when the car's key-switch is fully "on" and retracts when "off".
1999 - 2005's
The power antenna splitter model for 99 and later Miatas includes a switch, connecting wires, and wire taps. The switch connects in series with a wire to the power antenna's plug. Once the antenna is extended, switching the switch will maintain the antenna extended until the switch is returned to its normal position and the next up/down signal is sent by the Miata radio. The switch nicely installs, out of normal view, in an easy to access existing through-hole into the trunk that's under the upper corner of the Velcro-held vertical carpet behind the driver's seat.
ALTERNATE POWER ANTENNA STAY-UP METHODS
The splitter can be used with the power antenna without making any wiring changes if when using CB the Miata AM/FM radio is left "on" to keep the power antenna extended; or, by unplugging the antenna's power connector in the trunk while the antenna is in its extended position. For pre-97's a switch can be added to enable selecting the Miata's automatic radio/tape/CD control of the power antenna -- add the switch in series with the diode-connected wire taps (observe wire tap's color coded polarity when connecting) or for 97's, add a switch in series with the jumper wire.
CB RADIO INFORMATION
For club events a loner CB can be installed in a Miata in just seconds, including the antenna splitter.
Desirable CB Radio Features
When looking for a CB it's best to find one that will remember the last-set channel. Their instruction books don't always tell you if they do, and some that say they don't, actually do -- at least for more than long enough to stop to eat for a while. The CB should have some type of noise reduction feature, either a noise limiter, or noise blanker (blanker is usually better, and having both is better yet). Low cost CB radios do just fine. More expensive ones often have lots of knobs or settings that just aren't needed and can get miss-set to prevent communicating as desired. Essential controls are volume, squelch, and channel selection.
Types of CB Radios
CB's are available with all the controls and small speaker in a hand-held mike. Some of those have a connector box that can be mounted under or behind the seat, under the center console, or in the trunk. The connector box is nice to have because it enables having only one wire going to the mike unit, and most have a socket for plugging in a larger external speaker. Some with the connector box have a pig-tail lead for connection to the mike unit -- with the connector box placed in the trunk forward of the spare tire (pre-99) that pig-tail lead can be extended through the hole into the cab area for connection of the mike. Although that's a nice neat location for installing the CB's connector box, as well as under the center console, those locations prevent being able to conveniently plug-in/unplug an external speaker. So, you may prefer to install the connector box in the rear area of the trunk or for even greater plug-in convenience, in the car.
If you don't have the CD player installed, for pre-99's, there is space behind the dash, under the radio, for most any CB (for larger CB's, may require breaking or cutting a bracket out of the way). Hand-held CB's are another possibility. Many of them come with a cigarette lighter plug that can be simply plugged in. Some may not be loud enough to hear in a Miata at speed, and with so many wires going to the piece you talk into tangled wires can be a problem. In actual use in a Miata the built-in antenna on hand-held CB's have very limited, and typically inadequate, communications range. The low power Family Radio Service (FRS) radios used in Miatas typically have even less range.
CB 12-Volt Power from the Car
It's best to connect CB's to a key-switched power source so the Miata's battery won't run down if you forget to turn the CB off. A source of key-switched power in 92 - 96 Miatas is the blue/black wire at the car's power antenna connector in the trunk (for 97's -- the blue wire at the relay socket for defogger behind the trunk's rear trim panel; for 99's and later there's no key switched power in their trunk). For 90 - 97, there's key-switched power under the center console at the connector for power windows, the blue/white wire (for 99's and later -- brown).
Other sources for 90 - 97 are at the fuse box under the dash from the Cigar fuse, the blue/black wire, and behind the dash at the cigarette lighter, the blue/black wire. For the cigarette lighter in 99's and later, it's a yellow wire. For 99's and later, you may be able to pull the lighter socket's housing out by the edge of the chrome piece that's pressed fit into the surrounding plastic -- pulling with pliers covered by tape or a rag will help protect the chrome piece from being scratched.
Although not as critical because of the antenna splitter's design, it's usually best to keep the CB's grounding power lead short, and run direct to the body of the car.
Destin, FL 32541